Dry friction damper with damping force perpendicular to principal direction of a vibration

Abstract

In a body subject to a cyclic energy of such a nature as to cause the body to mechanically vibrate with a principal motion in a first direction, a dry friction damper has a first sliding element fixed to the body, the first sliding element having a first rigid dry sliding surface extending in a second direction having a component perpendicular to the first direction. A second stationary element has a second rigid dry sliding surface extending in the second direction. A normal force is applied between the first and second surfaces, resulting in damping of vibrations by dry friction damping.

What is claimed as new and desired to be secured by Letters Patent of the United States is: 
     
       1. In a body subject to cyclic energy of such a nature as to cause said body to mechanically vibrate with a principal motion in a first direction, a dry friction vibration damping means comprising: a first sliding element fixed to said body and having a first rigid dry sliding surface extending in a second direction having a component perpendicular to said first direction;   a second stationary, element having a second rigid surface engaging said first surface and extending in said second direction; and   means for applying a normal force between said first and second surfaces, whereby said vibrations are damped by dry friction damping.   
     
     
       2. The body of claim 1, wherein said body is elongate and has a first end fixed relative to said stationary element and a second end. 
     
     
       3. The body of claim 1, wherein said second direction is substantially perpendicular to said first direction. 
     
     
       4. The body of claim 2, wherein said second direction is substantially perpendicular to said first direction. 
     
     
       5. The body of claim 2, wherein said body is a turbine blade and said second end of said body is unconstrained. 
     
     
       6. The body of claim 5, wherein said first sliding element comprises a spring, and wherein said means for applying a normal force comprises a spring force of said spring. 
     
     
       7. The body of claim 6, wherein said second direction is perpendicular to said first direction. 
     
     
       8. The body of claim 2, wherein said second direction has a horizontal component, and wherein said means for applying a normal force comprises the weight of at least said body and first sliding element. 
     
     
       9. The body of claim 8, wherein said second end is supported for constraint against translational movement except between said first and second surfaces, and for rotation about an axis transverse to said first direction and to the length of said body. 
     
     
       10. The body of claim 9, wherein said second direction is perpendicular to said first direction. 
     
     
       11. The body of claim 10, wherein said second direction is horizontal. 
     
     
       12. The body of claim 11, wherein said means for applying a normal force further comprises an additional weight.